Fast multichannel time-resolved absorption measurements from 300-700 nm with nanosecond resolution will be used to examine the kinetics and mechanism of nitric oxide (NO) generation and ligand binding in nitric oxide synthase (NOS). The kinetics of NOS following ligand photolysis will be examined to determine details about the kinetics of protein relaxation and ligand recombination, providing structural information about protein function. Using multichannel time-resolved absorption spectroscopy, the fast kinetics of NOS catalysis following photoinduced electron-transfer and the rapid activation of oxygen by NOS after initiation by flow-flash mixing will be measured. These experiments will provide important information about how NOS produces NO endogenously. NO biology has been an intensive area of biomedical research as NO physiologically plays many significant roles in human physiology, including neurotransmission, vasodilation regulation, and cytotoxic actions of the immune system. Understanding NO synthesis will aid in drug development (for hypertension, atherosclerosis, diabetes) and therapeutic treatments (sickle cell anemia, blood substitutes, and septic shock) that utilize NO bioactivity. The fast multichannel experiments proposed here will help in elucidating the kinetics of how NOS produces NO endogenously, while providing research opportunities to undergraduate and master's students in biochemical methods and biophysical techniques.